The lindex command accepts a parameter, list, which
it treats as a Tcl list. It also accepts zero or more indices into
the list. The indices may be presented either consecutively on the
command line, or grouped in a
Tcl list and presented as a single argument.

If no indices are presented, the command takes the form:

lindex list

or

lindex list {}

In this case, the return value of lindex is simply the value of the
list parameter.

When presented with a single index, the lindex command
treats list as a Tcl list and returns the
index'th element from it (0 refers to the first element of the list).
In extracting the element, lindex observes the same rules
concerning braces and quotes and backslashes as the Tcl command
interpreter; however, variable
substitution and command substitution do not occur.
If index is negative or greater than or equal to the number
of elements in value, then an empty
string is returned.
The interpretation of each simple index value is the same as
for the command string index, supporting simple index
arithmetic and indices relative to the end of the list.

If additional index arguments are supplied, then each argument is
used in turn to select an element from the previous indexing operation,
allowing the script to select elements from sublists. The command,